1. Field of the Invention
The invention relates to a new type of fitting for use in pressure vessels. In particular, the invention relates to a pressure vessel fitting which is non-metallic, thus, eliminating the need for the soldering, brazing or welding of the fitting which is necessary when conventional metallic fittings are used. The corrosion problems often encountered when using metallic fittings are, thereby, eliminated. Also, in particular, the invention relates to a pressure vessel fitting having a snap together design which eliminates the loosening problems occurring due to vibration which threaded connections are subject to, unless some type of retention or locking device is used.
2. Description of Related Art
The plastic or non-metallic fitting connections and many of the metallic fitting connections currently in use in the pressure vessel industry are threaded together. Threaded connections are often subject to loosening problems under vibration, unless some type of retention or locking device is used. Metallic fittings are often brazed, soldered, or welded, which can result in corrosion problems.
U.S. Pat. No. 5,222,620 discloses a drum liner locking and locating apparatus for securing a drum liner to a drum. The drum liner apparatus primarily comprises a fitting, a liner, and a non-releasable securing means. The fitting is passed through an opening in the lid of a drum before the lid is attached to the drum. The fitting can only be passed through the opening so that the liner is in a position that the liner can expand to the full size of the drum. After the fitting is in place, the non-releasable securing means fastens the fitting to the drum raising the drum liner to the top of the drum. Consequently, to remove the drum liner, the top of the drum must be removed destroying the drum and prohibiting reconditioning or reuse of the drum. More specifically, the fitting (2) for the the drum (3) has the bottom flange (8) which contains the teeth (10). The gasket (6) fits on the top of the flange (8). The rim of the top hole of the drum (3) is located on the top of the gasket (16). The lock nut (20) holds the rim of the drum (3) in place.
U.S. Pat. No. 3,774,802 discloses apparatus for attaching internal parts to the interior of a pressure vessel having an inner lining of uncured rubber including a rigid fastener, preferably an internally threaded nut, rigidly secured over an opening through the wall of the vessel and the rubber lining. A rigid bolt is threaded through the nut from the inside of the vessel so that a lateral shoulder on the bolt is tightened against the rubber lining. A layer of uncured rubber is mounted over the shoulder, and the layer is cured when the inner lining is being cured to embed the shoulder in the rubber and seal the bolt against leakage. Internal parts are attached to the portion of the bolt inside the vessel, and the structural load applied to the bolt by the internal parts is transmitted to the wall of the vessel through the rigid bolt and nut. More specifically, the internally-threaded nut (16) is welded to the tank wall (10). The bolt (22) inwardly extends past the tank wall (10) and contains the flange (26). The end of the liner (12) is C-shape and fits over the flange (26).
European Published Patent Application No. 0415691 discloses a cap and seal closure for flexible containers. The mouthpiece (4) has the flanges (46, 47) sealed to the inner (82) and outer bags, and the connection plug (48) communicates (11) with the space between. The cap (20) has an inner hollow portion with a three layered metal foil disc. The inner bag (2) is filled via the opening (10). The cap (20) is secured by lodgement of the annular projections (45A, 45B). The disc is then fused to the end face (45c) of the mouthpiece (4). Thereafter, removal of the cap (20) leaves the disc seal in place retaining the sterlized state of the bag contents, while and until an extractor is fitted. The contents are said not to be exposed during fitting of an extraction device.
U.S. Pat. No. 3,095,993 discloses a seal arrangement for sealing the valve end of the valve body (22) and the end opening of the end cap (14) of the fiberglass tank (10). The lower end of the valve body (22) is T-shaped with the end protrusion thereof being externally threaded. The L-shaped end fitting (21) is internally threaded and mates with the end protrusion of the valve body (22). The rim of the end openings of the end cap (12) fits between the lower rim of the end fitting (21) and the rim of the valve body (22). The O-ring (23) is located between the rim of the valve body (22) and the rim of the end opening of the end cap (14).
U.S. Pat. No. 4,685,589 discloses a composite pressure vessel which includes a fluid port directly through the composite side wall structure formed by internally locating a porting fitting in the side wall structure and then inserting a liner member in the interior of the side wall structure. When thus assembled, a void space is provided between a flange portion on the radial inner end of the porting fitting and the liner member which is completely filled with a sealant. Then a porting hole is drilled through the sealant and liner member from the exterior fitting end. A nut may be threaded onto an exteriorly protruding end portion of the porting fitting and torqued to preload the porting fitting against the composite side wall structure. Also, composite material reinforcement may be applied locally around the protruding end portion and nut. More specifically, note the porting fitting (22) with the flange portion (30) on the inner end of the vessel (2).
Attention is also directed to U.S. Pat. Nos. 4,775,073; 2,376,351; 3,181,589; 4,589,563; 2,376,831 and 2,372,800.
U.S. Pat. Nos. 2,695,753; 3,035,614; 3,524,475; 3,931,834 and 4,836,409, for example, relate to expansion tanks for closed water systems. An expansion tank is divided into two non-communicating chambers by a flexible elastomeric diaphragm. One section is precharged with gas under pressure so that the diaphragm is displaced to increase or decrease the volume of this section according to the variations of the volume of water in the other section. When the expansion tank is incorporated in a hot water heating system, the variation in volume is caused when the boiler water is heated and cooled in the normal cyclic operation of the heating system. If the expansion tank is a part of a water system, the variation in volume occurs as tap water is drawn and when the pump operates to replace the water drawn from the tank. The diaphragm separates the gas in the one section of the tank from the water in the system, thereby eliminating the drawbacks of prior art heating systems or other water systems which result from the absorption of air in the water. The diaphragm type of expansion tank is one in which the inner surface of the portion of the tank defining the water-receiving section is usually covered with a water impervious liner. The liner itself is usually fabricated in a separate operation before being installed in the tank. The water is thus contained between the liner and the diaphragm so that the entire interior of the expansion tank is shielded from the water. As a result, corrosion of the tank is greatly reduced regardless of the type of water with which the tank is used or of the temperature experienced within the practical limits of operation of hot water heating systems. A problem sometimes exists in these types of expansion tanks due to air and/or water leakage at the seals around the water inlet port/fitting.
Note the resilient support (135) in U.S. Pat. No. 4,836,409.